1. Field Of The Invention
The present invention relates to sun screens which are used to provide protection from sunshine passing through the rear window of a hatchback automotive vehicle without obscuring visibility through the window.
2. Description Of The Prior Art
Various sun screens have been provided for mounting on the exterior of a window of an automotive vehicle to protect the upholstery and the occupants of the vehicle from direct sunshine passing through the window. Conventional sun screens are typically formed of stamped or assembled metal members which include a plurality of mutually parallel, horizontally disposed louvers that are joined together and secured to the window frame or exterior surface of the automotive vehicle body.
Sun screens are particularly desirable in automotive vehicles which have inclined rear windows. In many models of modern automobiles, the rear windows are inclined to form a relatively small angle with respect to the horizontal, as contrasted with the rear windows of automobiles manufactured in earlier years. Contemporary vehicles having inclined rear windows of this type are commonly referred to as "hatchback" model automobiles, due to the fact that the rear window is mounted in an upwardly rotatable lid that provides access to the vehicle trunk. The rear windows in conventional hatchback style vehicles are preferably inclined relative to the horizontal from between about 15 degrees to about 40 degrees. The inclination of a sloping rear window of a hatchback style automotive vehicle exposes the upholstery of the vehicle to rapid deterioration resulting from the visible and infra-red radiation which passes through the window. The extent of exposure to the sun is greatly enhanced when the normal orientation of a vehicle window is at a significant angular slope. In hatchback style vehicles windows are generally far more expansive in area than windows which are oriented in a generally upright disposition so as to provide the vehicle occupants with an adequate field of view. Due to the enhanced surface area and the angle of inclination of such a window, degradation of upholstery and discomfort to the vehicle occupants is a very significant problem. Furthermore, hatchback style vehicles having sloped or inclined windows have, in recent years, gained considerable popularity for a variety of reasons.
Conventional, externally mounted automobile vehicle window sun screens are constructed so as to adequately shield the interior of the vehicle from the sun and to afford the driver and the other vehicle occupants with good visibility. However, conventional, externally mounted vehicle window sun screens have several very significant disadvantages. When a sun screen is mounted on the exterior of an automotive vehicle window frame, it creates a considerable wind noise while the vehicle is traveling. The wind noise by itself is quite annoying to the driver and other occupants of the vehicle. Moreover, due in large part to the considerable buffeting of the sun screen by the wind, conventional devices tend to rattle quite loudly while the vehicle is under way. Conventional, externally mounted sun screens are generally constructed of a number of assembled metal parts. The manner of fabrication not only adds to the cost of such devices, but the parts tend to rattle together and against the surface of the vehicle window when the vehicle is in moton.
A further significant disadvantage of conventional vehicle window sun screens involves the aerodynamic drag which such externally mounted screens exert upon the vehicle. Such aerodynamic drag reduces the efficiency of vehicle fuel consumption, to some extent, and also contributes significantly to rattling and wind noise due to enhanced vibration of the component parts of the sun screen.
Another disadvantage of conventional vehicle window screens is that the framework and louvers are typically designed to fit only a single, specific vehicle model. The framework of conventional vehicle screens normally has a fixed, generally rectangular configuration which is suitable for mounting only upon a window of a particular size. Likewise, the louvers are of fixed length and extend the fixed distance between the edge rails of the framework. As a result, a particular sun screen has very little flexibility of application, and numerous different models of sun screens are necessary to accomodate the different models of hatchback vehicles available. A dealer in sun screens must therefore inventory an excessivly large stock in order to be able to accomodate a reasonable number of different vehicles. The cost of maintaining such a large inventory adds considerably to the cost of dealing in such devices. This cost, quite naturally, is passed along to the ultimate user.